As electronics has progressed in recent years, the reduction in size and increase in capacity of electronic components such as monolithic ceramic capacitors have advanced rapidly.
For such electronic components, for example, a monolithic ceramic capacitor is usually manufactured in such a way that after an outer electrode conductive paste is applied to both end portions of a component body in which inner electrodes are embedded, outer electrodes are formed by calcination, plated coatings of Ni, Sn, or the like are formed on both end portions of each outer electrode in order to increase the heat resistance or wettability of the outer electrodes, and the outer electrodes are covered with the plated coatings.
Patent Document 1 proposes outer electrodes of an electronic component that each include a first layer in contact with a bare chip including a ceramic sintered body and a second layer placed on the first layer. In each outer electrode, the first layer is made from a conductive paste containing an organic binder, an organic solvent, and a metal resinate dispersed in the organic binder and the organic solvent and the second layer is made from a conductive paste containing a thermosetting resin, an organic solvent, and a metal powder dispersed in the thermosetting resin and this organic solvent.
In Patent Document 1, the conductive contact between the ceramic sintered body (bare chip) and the outer electrode is enhanced with the first layer and a dense metal layer is formed by calcining fine metal particles (metal resinate) so as to prevent the ingress of an electrolyte solution during wet etching. Since the second layer, which is made from the conductive paste as described above, has the good effect of absorbing and dispersing mechanical stress, the electronic component has good plating solution resistance, excellent electrical characteristics, excellent reliability, and excellent mechanical strength.
Patent Document 2 proposes outer electrodes of a chip-type electronic component that are in contact with surfaces of a bare chip including a ceramic sintered body. The outer electrodes are made from a conductive paste containing an organic binder, an organic solvent, and a metal resinate dispersed in the organic binder and the organic solvent.
In Patent Document 2, dense electrode layers are formed by sintering ultrafine metal particles produced by decomposing the metal resinate, whereby the ingress of an electrolyte solution is prevented during wet etching. Since the use of the above conductive paste enables the outer electrodes to be thinly formed, the stress of the outer electrodes to the bare chip is small and therefore cracking is unlikely to occur after packaging. This, as well as Patent Document 1, allows the chip-type electronic component to have excellent electrical characteristics, reliability, and mechanical strength.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 9-190950 (claim 1, paragraphs [0010] to [0012], and the like)
Patent Document 2: Japanese Unexamined Patent Application Publication No. 9-266129 (claim 1, paragraphs [0010] to [0012], and the like)